Electrically conductive compositions and method of manufacture thereof

ABSTRACT

Disclosed herein is a method of manufacturing an electrically conductive composition comprising reducing the viscosity of a molten masterbatch to form a reduced viscosity molten masterbatch; and mixing the reduced viscosity molten masterbatch with a polymer to form the electrically conductive composition. Disclosed herein too is a method of manufacturing an electrically conductive composition comprising mixing a molten masterbatch with a first polymer in a first extruder, wherein the first polymer has a melt viscosity that is lower than the melt viscosity of the molten masterbatch; reducing the melt viscosity of the molten masterbatch to form a reduced viscosity molten masterbatch; and mixing the reduced viscosity molten masterbatch with a second polymer in a second extruder to form the electrically conductive composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. application Ser. No. 11/057,946filed 15 Feb. 2005.

BACKGROUND

This disclosure relates to electrically conductive compositions andmethods of manufacture thereof.

Articles made from polymers are commonly utilized in material-handlingand electronic devices such as packaging film, chip carriers, computers,printers and photocopier components where electrostatic dissipation orelectromagnetic shielding are important requirements. Electrostaticdissipation (hereinafter ESD) is defined as the transfer ofelectrostatic charge between bodies at different potentials by directcontact or by an induced electrostatic field. Electromagnetic shielding(hereinafter EM shielding) effectiveness is defined as the ratio (indecibels) of the proportion of an electromagnetic field incident uponthe shield that is transmitted through it. As electronic devices becomesmaller and faster, their sensitivity to electrostatic charges isincreased and hence it is generally desirable to utilize polymers thathave been modified to provide improved electrostatically dissipativeproperties. In a similar manner, it is desirable to modify polymers sothat they can provide improved electromagnetic shielding whilesimultaneously retaining some or all of the advantageous mechanicalproperties of the polymers.

Conductive fillers such as graphite fibers derived from pitch andpolyacrylonitrile having diameters larger than 2 micrometers are oftenincorporated into polymers to improve the electrical properties andachieve ESD and EM shielding. However, because of the large size ofthese graphite fibers, the incorporation of such fibers generally causesa decrease in the mechanical properties such as impact. In addition,incomplete dispersion of the carbon fibers promotes inhomogeneity withinarticles derived from the composition. There accordingly remains a needin the art for conductive polymeric compositions, which while providingadequate ESD and EM shielding, can retain their mechanical properties.There also remains a need for methods wherein the electricallyconductive fillers can be dispersed in such a manner so as to minimizeinhomogeneity in article derived from the composition.

FIGURES

FIG. 1 is a depiction of an exemplary embodiment of the extrusion system10 reflecting a first extruder 12 and a second extruder 16. The outputfrom the first extruder 12 is fed into the second extruder 16; and

FIG. 2 depicts the extruder with the side feeder and the side compounderthat was used for the preparation of Sample #'s 1 through 20.

SUMMARY

Disclosed herein is a method of manufacturing an electrically conductivecomposition comprising reducing the viscosity of a molten masterbatch toform a reduced viscosity molten masterbatch; and mixing the reducedviscosity molten masterbatch with a polymer to form the electricallyconductive composition.

Disclosed herein too is a method of manufacturing an electricallyconductive composition comprising mixing a molten masterbatch with afirst polymer in a first extruder, wherein the first polymer has a meltviscosity that is lower than the melt viscosity of the moltenmasterbatch; reducing the melt viscosity of the molten masterbatch toform a reduced viscosity molten masterbatch; and mixing the reducedviscosity molten masterbatch with a second polymer in a second extruderto form the electrically conductive composition.

Disclosed herein too is a method of manufacturing an electricallyconductive composition comprising mixing a molten masterbatch with apolyamide in a first extruder, wherein the polyamide has a meltviscosity that is lower than the melt viscosity of the moltenmasterbatch; reducing the melt viscosity of the molten masterbatch toform a reduced viscosity molten masterbatch; and mixing the reducedviscosity molten masterbatch with a polyarylene ether in a secondextruder to form the electrically conductive composition.

Disclosed herein too is a method of manufacturing a compositioncomprising melting a masterbatch to form a molten masterbatch in a firstextruder; and mixing the molten masterbatch with a polymer in a secondextruder to form the composition.

DETAILED DESCRIPTION

Disclosed herein are methods for manufacturing electrically conductivecompositions comprising polymers and electrically conductive fillers,such that the electrically conductive compositions have a bulk volumeresistivity of less than or equal to about 10e⁸ ohm-cm, while displayingimpact properties greater than or equal to about 10 kilojoules/squaremeter and a Class A surface finish. The method advantageously involvesmelt blending a masterbatch with a molten polymer to improvedistribution of electrically conductive filler in the electricallyconductive composition. In one embodiment, the method advantageouslyinvolves reducing the viscosity of a masterbatch prior to mixing with amolten polymer to form the electrically conductive composition. Themolten masterbatch comprises electrically conductive filler. Thereduction in viscosity of the molten masterbatch takes place in a firstextruder which acts as a side compounder for a second extruder. Thereduction in viscosity can be brought about by adding to the moltenmasterbatch a diluent, a plasticizer, or a polymer having a lower meltviscosity than the melt viscosity of the masterbatch.

The method can also advantageously be used to facilitate the dispersionof additives and fillers, other than electrically conductive fillers ina composition. Thus, in one embodiment, a molten masterbatch containingadditives and/or fillers that are not electrically conductive can bemelt blended with a molten polymer to obtain a composition. In anotherembodiment, the method advantageously involves reducing the viscosity ofa molten masterbatch prior to mixing with a molten polymer to form acomposition that comprise non-electrically conductive fillers and/oradditives. In yet another embodiment, the composition can comprise amixture of non-conductive additives and fillers as well as electricallyconductive fillers.

In one embodiment, a masterbatch is first melt blended in the firstextruder. The molten masterbatch is then mixed with a second polymer ina second extruder to form the electrically conductive composition. Theelectrically conductive composition is then extruded from the secondextruder. As noted above, the composition is electrically conductiveonly when the filler is electrically conductive.

In one embodiment, a first polymer and the molten masterbatch are mixedin the first extruder to form a reduced viscosity molten masterbatch.The reduced viscosity molten masterbatch is then mixed with a secondpolymer in a second extruder to form the electrically conductivecomposition. The electrically conductive composition is then extrudedfrom the second extruder.

With reference now to the FIG. 1, an exemplary extrusion system 10reflects first extruder 12 and a second extruder 16. The first extruder12 also referred to as a side compounder feeds a molten mixture of themasterbatch and a first polymer into the second extruder 16 that servesas the main extruder. The first polymer has a melt viscosity that islower than the melt viscosity of the masterbatch. The mixing of thefirst polymer with the masterbatch reduces the melt viscosity of themasterbatch. The molten mixture of the masterbatch and the first polymeris termed the reduced viscosity molten masterbatch. Reducing theviscosity of the molten masterbatch in the first extruder prior tomixing with the second polymer in the second extruder facilitates bettermixing.

The second extruder 16 also contains the second polymer in the moltenstate. The reduced viscosity molten masterbatch is mixed with the secondpolymer in the second extruder 16 to form the electrically conductivecomposition. In one embodiment, it is desirable for the viscosity of themolten masterbatch to be equal to the viscosity of the molten secondpolymer at the point of contact of the two melts. Without being limitedby theory, it is believed that when the melt viscosity of the reducedviscosity molten masterbatch equals the melt viscosity of the secondpolymer, optimal mixing of the polymers can be achieved. This optimalmixing permits a better dispersion of the electrically conductivefiller.

This method can be utilized to manufacture electrically conductivecompositions having a surface resistivity greater than or equal to about10⁸ ohm/square (ohm/sq) while having a bulk volume resistivity of lessthan or equal to about 10e⁸ ohm-cm, while displaying impact propertiesgreater than or equal to about 10 kilojoules/square meter and a Class Asurface finish. In another embodiment, the method can be used tomanufacture electrically conductive compositions having uniformelectrical conductivity in mutually perpendicular directions, thusminimizing any inhomogeneity in the electrical conductivity across thebulk of the electrically conductive composition.

Such electrically conductive compositions can be advantageously utilizedin computers, electronic goods, semi-conductor components, circuitboards, or the like which need to be protected from electrostaticdissipation. They may also be used advantageously in automotive bodypanels both for interior and exterior components of automobiles that canbe electrostatically painted if desired.

The first polymer and the second polymer used in the electricallyconductive compositions may be selected from a wide variety ofthermoplastic resins, blends of thermoplastic resins, or blends ofthermoplastic resins with thermosetting resins. The first and secondpolymers may also be a blend of polymers, copolymers, terpolymers, orcombinations comprising at least one of the foregoing polymers.Specific, but non-limiting examples of thermoplastic polymers includepolyacetals, polyacrylics, polyarylene ethers, polycarbonates,polystyrenes, polyesters, polyamides, polyamideimides, polyarylates,polyurethanes, polyarylsulfones, polyethersulfones, polyarylenesulfides, polyvinyl chlorides, polysulfones, polyetherimides,polytetrafluoroethylenes, polyetherketones, polyether etherketones, orthe like, or a combination comprising at least one of the foregoingthermoplastic polymers.

Specific non-limiting examples of blends of thermoplastic polymersinclude acrylonitrile-butadiene-styrene/nylon,polycarbonate/acrylonitrile-butadiene-styrene, polyphenyleneether/polystyrene, polyphenylene ether/polyamide,polycarbonate/polyester, polyphenylene ether/polyolefin, andcombinations comprising at least one of the foregoing blends ofthermoplastic polymers.

In one embodiment, the first and second polymers are different from eachother. In another embodiment, the first polymer is of the samecomposition as the second polymer. When the first polymer is of the samecomposition as the second polymer, the molecular weight and hence themelt viscosity of the first polymer can be greater than the molecularweight and the melt viscosity of the second polymer. In an exemplaryembodiment, the first polymer is a polyarylene ether, while the secondpolymer is a polyamide. The polyarylene ether may be compatibilized withpolyamide if desired.

Polyarylene ethers per se, are known polymers comprising a plurality ofstructural units of the formula (I):

wherein for each structural unit, each Q¹ is independently halogen,primary or secondary lower alkyl (e.g., alkyl containing up to 7 carbonatoms), phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, orhalohydrocarbonoxy wherein at least two carbon atoms separate thehalogen and oxygen atoms; and each Q² is independently hydrogen,halogen, primary or secondary lower alkyl, phenyl, haloalkyl,hydrocarbonoxy or halohydrocarbonoxy as defined for Q¹. In an exemplaryembodiment, each Q¹ is alkyl or phenyl, especially C₁₋₄ alkyl, and eachQ² is hydrogen.

Both homopolymer and copolymer polyarylene ethers are included.Exemplary homopolymers are those containing 2,6-dimethylphenylene etherunits. Suitable copolymers include random copolymers containing, forexample, such units in combination with 2,3,6-trimethyl-1,4-phenyleneether units or copolymers derived from copolymerization of2,6-dimethylphenol with 2,3,6-trimethylphenol. Also included arepolyarylene ethers containing moieties prepared by grafting vinylmonomers or polymers such as polystyrenes; and coupled polyarylene etherin which coupling agents such as low molecular weight polycarbonates,quinones, heterocycles and formals that undergo reaction in a knownmanner with the hydroxy groups of two polyarylene ether chains toproduce a higher molecular weight polymer.

The polyarylene ether generally has a number average molecular weight ofabout 3,000 to about 40,000 and a weight average molecular weight ofabout 20,000 to about 80,000, as determined by gel permeationchromatography (GPC). The polyarylene ether generally has an intrinsicviscosity of about 0.10 to about 0.60 deciliters per gram (dl/g) whenmeasured in chloroform at 25° C. In another embodiment, the polyaryleneether generally has an intrinsic viscosity about 0.29 to about 0.48dl/g, when measured in chloroform at 25° C. It is also possible toutilize a high intrinsic viscosity polyarylene ether and a low intrinsicviscosity polyarylene ether in combination as long as the combinationhas an intrinsic viscosity of about 0.10 to about 0.60 dl/g.

The polyarylene ethers are generally prepared by the oxidative couplingof at least one monohydroxyaromatic compound such as 2,6-xylenol or2,3,6-trimethylphenol. Catalyst systems are generally employed for suchcoupling; they generally contain at least one heavy metal compound suchas a copper, manganese or cobalt compound, usually in combination withvarious other materials.

Particularly useful polyarylene ethers for many purposes are those thatcomprise molecules having at least one aminoalkyl-containing end group.The aminoalkyl radical is located in an ortho position to the hydroxygroup. Products containing such end groups may be obtained byincorporating an appropriate primary or secondary monoamine such asdi-n-butylamine or dimethylamine as one of the constituents of theoxidative coupling reaction mixture. Also frequently present are4-hydroxybiphenyl end groups, generally obtained from reaction mixturesin which a by-product diphenoquinone is present, especially in acopper-halide-secondary or tertiary amine system. A substantialproportion of the polymer molecules, generally constituting as much asabout 90% by weight of the polymer, may contain at least one of saidaminoalkyl-containing and 4-hydroxybiphenyl end groups.

Useful polyamides are a generic family known as nylons, characterized bythe presence of an amide group (—C(O)NH—). Nylon-6 and nylon-6,6 areexemplary polyamides and are available from a variety of commercialsources. Other polyamides, however, such as nylon-4,6, nylon-12,nylon-6,10, nylon 6,9, nylon 6/6T and nylon 6,6/6T with triaminecontents of less than or equal to about 0.5 weight percent (wt %), aswell as others, such as the amorphous nylons may be useful forparticular polyarylene ether-polyamide applications. Mixtures of variouspolyamides, as well as various polyamide copolymers, are also useful.The most preferred polyamide for the blends of the present invention isnylon-6,6. Polyamides having viscosity of up to about 400 millilitersper gram (ml/g) as measured in a 0.5 wt % solution in 96 wt % sulfuricacid in accordance with ISO 307.

The first polymer is generally used in amounts of about 5 to about 95weight percent (wt %), based on the total weight of the electricallyconductive composition. In one embodiment, the first polymer isgenerally used in amounts of about 15 to about 90 wt %, based on thetotal weight of the electrically conductive composition. In anotherembodiment, the first polymer is generally used in amounts of about 30to about 80 wt %, based on the total weight of the electricallyconductive composition. In yet another embodiment, the first polymer isgenerally used in amounts of about 35 to about 75 wt %, based on thetotal weight of the electrically conductive composition.

The second polymer is generally used in amounts of about 5 to about 95weight percent (wt %), based on the total weight of the electricallyconductive composition. In one embodiment, the second polymer isgenerally used in amounts of about 15 to about 90 wt %, based on thetotal weight of the electrically conductive composition. In anotherembodiment, the second polymer is generally used in amounts of about 30to about 80 wt %, based on the total weight of the electricallyconductive composition. In yet another embodiment, the second polymer isgenerally used in amounts of about 35 to about 75 wt %, based on thetotal weight of the electrically conductive composition.

The first and second polymers are generally used in amounts of 90 to99.99 wt %, based on the weight of the electrically conductivecomposition. In one embodiment, the first and second polymer aregenerally used in amounts of 92 to 98 wt %, based on the weight of theelectrically conductive composition. In another embodiment, the firstand second polymers are generally used in amounts of 93 to 97 wt %,based on the weight of the electrically conductive composition. Inanother embodiment, the first and second polymers are generally used inamounts of 94 to 96 wt %, based on the weight of the electricallyconductive composition.

Various additives may be added to the electrically conductivecomposition. Exemplary additives are compatibilizing agents, impactmodifiers, mold release agents, antioxidants, antiozonants, thermalstabilizers, or the like, or a combination comprising at least one ofthe foregoing additives.

Electrically conductive fillers that can be added to the electricallyconductive composition are carbon nanotubes, carbon fibers, carbonblack, metallic fillers, non-conductive fillers coated with metalliccoatings, electrically conductive non-metallic fillers, or the like, ora combination comprising at least one of the foregoing electricallyconductive fillers.

Carbon nanotubes that can be used in the electrically conductivecomposition are single wall carbon nanotubes (SWNTs), multiwall carbonnanotubes (MWNTs), or vapor grown carbon fibers (VGCF). Single wallcarbon nanotubes (SWNTs) used in the composition may be produced bylaser-evaporation of graphite, carbon arc synthesis or a high-pressurecarbon monoxide conversion process (HIPCO) process. These SWNTsgenerally have a single wall comprising a graphene sheet with outerdiameters of about 0.7 to about 2.4 nanometers (nm). The SWNTs maycomprise a mixture of metallic SWNTs and semi-conducting SWNTs. MetallicSWNTs are those that display electrical characteristics similar tometals, while the semi-conducting SWNTs are those that are electricallysemi-conducting. In order to minimize the quantity of SWNTs utilized inthe composition, it is generally desirable to have the compositioncomprise as large a fraction of metallic SWNTs as possible. SWNTs havingaspect ratios of greater than or equal to about 5 are generally utilizedin the compositions. While the SWNTs are generally closed structureshaving hemispherical caps at each end of the respective tubes, it isenvisioned that SWNTs having a single open end or both open ends mayalso be used. The SWNTs generally comprise a central portion, which ishollow, but may be filled with amorphous carbon.

MWNTs derived from processes such as laser ablation and carbon arcsynthesis, may also be used in the electrically conductive compositions.MWNTs have at least two graphene layers bound around an inner hollowcore. Hemispherical caps generally close both ends of the MWNTs, but itmay desirable to use MWNTs having only one hemispherical cap or MWNTs,which are devoid of both caps. MWNTs generally have diameters of about 2to about 50 nm. When MWNTs are used, it is desirable to have an averageaspect ratio greater than or equal to about 5. In one embodiment, theaspect ratio of the MWNTs is greater than or equal to about 100, whilein another embodiment, the aspect ratio of the MWNTs is greater than orequal to about 1000.

Vapor grown carbon fibers (VGCF) may also be used in the electricallyconductive composition. These are generally manufactured in a chemicalvapor deposition process. VGCF having “tree-ring” or “fishbone”structures may be grown from hydrocarbons in the vapor phase, in thepresence of particulate metal catalysts at moderate temperatures, i.e.,about 800 to about 1500° C. In the “tree-ring” structure a multiplicityof substantially graphitic sheets are coaxially arranged about the core.In the “fishbone” structure the fibers are characterized by graphitelayers extending from the axis of the hollow core.

VGCF having diameters of about 3.5 to about 2000 nanometers (nm) andaspect ratios greater than or equal to about 5 may be used. When VGCFare used, diameters of about 3.5 to about 500 nm are desirable, withdiameters of about 3.5 to about 100 nm being more desirable, anddiameters of about 3.5 to about 50 nm being most desirable. It is alsodesirable for the VGCF to have average aspect ratios greater than orequal to about 100. In one embodiment, the VGCF can have aspect ratiosgreater than or equal to about 1000.

Carbon nanotubes are generally used in amounts of about 0.001 to about80 wt % of the total weight of the electrically conductive composition.In one embodiment, carbon nanotubes are generally used in amounts ofabout 0.25 wt % to about 30 wt %, based on the weight of theelectrically conductive composition. In another embodiment, carbonnanotubes are generally used in amounts of about 0.5 wt % to about 10 wt%, based on the weight of the electrically conductive composition. Inyet another embodiment, carbon nanotubes are generally used in amountsof about 1 wt % to about 5 wt %, based on the weight of the electricallyconductive composition.

Various types of electrically conductive carbon fibers may also be usedin the electrically conductive composition. Carbon fibers are generallyclassified according to their diameter, morphology, and degree ofgraphitization (morphology and degree of graphitization beinginterrelated). These characteristics are presently determined by themethod used to synthesize the carbon fiber. For example, carbon fibershaving diameters down to about 5 micrometers, and graphene ribbonsparallel to the fiber axis (in radial, planar, or circumferentialarrangements) are produced commercially by pyrolysis of organicprecursors in fibrous form, including phenolics, polyacrylonitrile(PAN), or pitch.

The carbon fibers generally have a diameter of greater than or equal toabout 1,000 nanometers (1 micrometer) to about 30 micrometers. In oneembodiment, the fibers can have a diameter of about 2 to about 10micrometers. In another embodiment, the fibers can have a diameter ofabout 3 to about 8 micrometers.

Carbon fibers are used in amounts of about 0.001 to about 50 wt % of thetotal weight of the electrically conductive composition. In oneembodiment, carbon fibers are used in amounts of about 0.25 wt % toabout 30 wt %, based on the weight of the electrically conductivecomposition. In another embodiment, carbon fibers are used in amounts ofabout 0.5 wt % to about 20 wt %, based on the weight of the electricallyconductive composition. In yet another embodiment, carbon fibers areused in amounts of about 1 wt % to about 10 wt %, based on the weight ofthe electrically conductive composition.

Carbon black may also be used in the electrically conductivecomposition. Exemplary carbon blacks are those having average particlesizes less than about 200 nm. In one embodiment, carbon blacks havingparticle sizes of less than about 100 nm can be used. In anotherembodiment, carbon blacks having particle sizes of less than about 50 nmcan be used. Exemplary carbon blacks may also have surface areas greaterthan about 200 square meter per gram (m²/g). In one embodiment, thecarbon blacks can have surface areas of greater than about 400 m²/g. Inanother embodiment, the carbon blacks can have surface areas of greaterthan about 1000 m²/g. Exemplary carbon blacks may have a pore volume(dibutyl phthalate absorption) greater than about 40 cubic centimetersper hundred grams (cm³/100 g). In one embodiment, the carbon blacks canhave surface areas of greater than about 100 cm³/100 g. In anotherembodiment, the carbon blacks can have surface areas of greater thanabout 150 cm³/100 g. In one embodiment, it is desirable for the carbonblack to have a low ionic content (chlorides, sulfates, phosphates,fluorides, and nitrates) of less than or equal to about 4 parts permillion per gram (ppm/g). Exemplary carbon powders include the carbonblack commercially available from Columbian Chemicals under the tradename CONDUCTEX®; the acetylene black available from Chevron Chemical,under the trade names S.C.F.® (Super Conductive Furnace) and E.C.F.®(Electric Conductive Furnace); the carbon blacks available from CabotCorp. under the trade names VULCAN XC72® and BLACK PEARLS®; and thecarbon blacks commercially available from Akzo Co. Ltd under the tradenames KETJEN BLACK EC 300® AND EC 600®.

Carbon black is used in amounts of about 0.01 to about 50 wt % of thetotal weight of the electrically conductive composition. In oneembodiment, carbon black is used in amounts of about 0.25 wt % to about30 wt %, based on the weight of the electrically conductive composition.In another embodiment, carbon black is used in amounts of about 0.5 wt %to about 20 wt %, based on the weight of the electrically conductivecomposition. In yet another embodiment, carbon black is used in amountsof about 1 wt % to about 10 wt %, based on the weight of theelectrically conductive composition.

Solid conductive metallic fillers may also be used in the electricallyconductive compositions. These may be electrically conductive metals oralloys that do not melt under conditions used in incorporating them intothe thermoplastic polymers, and fabricating finished articles therefrom.Metals such as aluminum, copper, magnesium, chromium, tin, nickel,silver, iron, titanium, or the like, or a combination comprising atleast one of the foregoing metals can be incorporated. Physical mixturesand true alloys such as stainless steels, bronzes, or the like, can alsoserve as conductive fillers. In addition, a few intermetallic chemicalcompounds such as borides, carbides, or the like, of these metals,(e.g., titanium diboride) can also serve as conductive filler particles.Solid non-metallic, conductive filler particles such as tin-oxide,indium tin oxide, antimony oxide, or the like, or a combinationcomprising at least one of the foregoing fillers may also be added torender the thermoplastic resins conductive. The solid metallic andnon-metallic conductive fillers may exist in the form of powder, drawnwires, strands, fibers, tubes, nanotubes, flakes, laminates, platelets,ellipsoids, discs, and other commercially available geometries.

Regardless of the exact size, shape and composition of the solidmetallic and non-metallic conductive filler particles, they may bedispersed into the electrically conductive composition of loadings of0.01 to about 50 wt %, based on the weight of the electricallyconductive composition. In one embodiment, the solid metallic andnon-metallic conductive filler particles may be used in amounts of about0.25 wt % to about 30 wt %, based on the weight of the electricallyconductive composition. In another embodiment, the solid metallic andnon-metallic conductive filler particles may be used in amounts of about0.5 wt % to about 20 wt %, based on the weight of the electricallyconductive composition. In yet another embodiment, the solid metallicand non-metallic conductive filler particles may be used in amounts ofabout 1 wt % to about 10 wt %, based on the weight of the electricallyconductive composition.

Non-conductive, non-metallic fillers that have been coated over asubstantial portion of their surface with a coherent layer of solidconductive metal may also be used in the electrically conductivecompositions. The non-conductive, non-metallic fillers are commonlyreferred to as substrates, and substrates coated with a layer of solidconductive metal may be referred to as “metal coated fillers”. Typicalconducting metals such as aluminum, copper, magnesium, chromium, tin,nickel, silver, iron, titanium, and mixtures comprising any one of theforegoing metals may be used to coat the substrates. Examples of suchsubstrates include silica powder, such as fused silica and crystallinesilica, boron-nitride powder, boron-silicate powders, alumina, magnesiumoxide (or magnesia), wollastonite, including surface-treatedwollastonite, calcium sulfate (as its anhydride, dihydrate ortrihydrate), calcium carbonate, including chalk, limestone, marble andsynthetic, precipitated calcium carbonates, generally in the form of aground particulates, talc, including fibrous, modular, needle shaped,and lamellar talc, glass spheres, both hollow and solid, kaolin,including hard, soft, calcined kaolin, and kaolin comprising variouscoatings to facilitate compatibility with the polymeric matrix resin,mica, feldspar, silicate spheres, flue dust, cenospheres, fillite,aluminosilicate (atmospheres), natural silica sand, quartz, quartzite,perlite, tripoli, diatomaceous earth, synthetic silica, and mixturescomprising any one of the foregoing. All of the above substrates may becoated with a layer of metallic material for use in the electricallyconductive compositions.

Other commonly used non-conductive mineral fillers such as siliconcarbide, molybdenum sulfide, zinc sulfide, aluminum silicate (mullite),synthetic calcium silicate, zirconium silicate, barium titanate, bariumferrite, barium sulfate, and flaked fillers such as glass flakes, flakedsilicon carbide, aluminum diboride, may also be used as substrates forconductive metallic coatings. Fibrous fillers such as aluminumsilicates, aluminum oxides, magnesium oxides, and calcium sulfatehemihydrate may also be coated with conductive metallic coatings andused in the electrically conductive compositions. Other fibrous fillerswhich may be used as substrates for conductive metallic coatings includenatural fillers and reinforcements, such as wood flour obtained bypulverizing wood, and fibrous products such as cellulose, cotton, sisal,jute, starch, cork flour, lignin, ground nut shells, corn, rice grainhusks, or the like. Also included among fibrous fillers that can be usedas substrates for conductive metallic coatings are single crystal fibersor “whiskers” including silicon carbide, alumina, boron carbide, andmixtures comprising any one of the foregoing. Glass fibers, includingtextile glass fibers such as E, A, C, ECR, R, S, D, and NE glasses andquartz, or the like, or a combination comprising at least one of theforegoing glass fibers may also be coated with a conductive metalliccoating and used in the electrically conductive composition.

Organic reinforcing fibrous fillers which can be used as substrates forconductive metallic coatings include fibers obtained from organicpolymers such as poly(ether ketone), polyetherimide, polybenzoxazole,poly(phenylene sulfide), polyesters, polyethylene, aromatic polyamides,aromatic polyetherimides or polyetherimides, polytetrafluoroethylene,acrylic resins, poly(vinyl alcohol), and other polymers. Suchreinforcing fillers may be provided in the form of monofilament ormultifilament fibers and can be used either alone or in combination withother types of fiber, through, for example, co-weaving or core/sheath,side-by-side, orange-type or matrix and fibril constructions, or byother methods known to one skilled in the art of fiber manufacture.Typical cowoven structures that can be used as substrates include glassfiber-carbon fiber, carbon fiber-aromatic polyetherimide (aramid) fiber,and aromatic polyetherimide fiberglass fiber. Fibrous fillers to be usedas substrates for conductive metallic coatings may be supplied in theform of, for example, rovings, woven fibrous reinforcements, such as0-90 degree fabrics, non-woven fibrous reinforcements such as continuousstrand mat, chopped strand mat, tissues, papers and felts and3-dimensional woven reinforcements, preforms, braids, and mixturescomprising any one of the foregoing.

Regardless of the exact size, shape and composition of said substrates,they are coated with a solid layer of conductive metal covering fromabout 5% of the surface area to 100% of the surface area. The surfacearea is typically determined by commonly known methods such as BETnitrogen adsorption or mercury porosimetry. In one embodiment, the metalcoated fillers may be used in amounts of about 0.25 wt % to about 50 wt%, based on the weight of the electrically conductive composition. Inanother embodiment, the metal coated fillers may be used in amounts ofabout 0.5 wt % to about 30 wt %, based on the weight of the electricallyconductive composition. In yet another embodiment, the metal coatedfillers may be used in amounts of about 1 wt % to about 20 wt %, basedon the weight of the electrically conductive composition.

In one embodiment carbon fibers, VGCF, carbon nanotubes, carbon black,conductive metal fillers, conductive non-metal fillers, metal coatedfillers as detailed above, or any combination of the foregoing may beused in the electrically conductive composition to render theelectrically conductive composition electrostatically dissipative. Anexemplary electrically conductive filler is carbon nanotubes. It isgenerally desirable to use the conductive fillers in amounts effectiveto produce surface resistivity less than or equal to about 10⁹ohm/square as measured as per ASTM D 257. In another embodiment, it isdesirable of have the surface resistivity of the electrically conductivecomposition be less than or equal to about 10⁷ ohm/square. In yetanother embodiment, it is desirable of have the surface resistivity ofthe electrically conductive composition be less than or equal to about10⁵ ohm/square.

It is also desirable to have the specific volume resistivity (SVR) ofthe electrically conductive composition less than or equal to about 10¹²ohm-centimeter. In one embodiment, it is desirable to have the volumeresistivity less than or equal to about 10⁶ ohm-centimeter. In anotherembodiment, it is desirable to have the volume resistivity less than orequal to about 10³ ohm-centimeter. In yet another embodiment, it isdesirable to have the volume resistivity less than or equal to about 100ohm-centimeter. In conjunction with the volume resistivity of less thanor equal to about 10¹² ohm-centimeter, it is desirable for theelectrically conductive composition to have a notched Izod impactstrength of greater than or equal to about 10 kilojoules/square meterand a Class A surface finish. In one embodiment, it is desirable to havea notched Izod impact strength of greater than or equal to about 15kilojoules/square meter. In another embodiment, it is desirable to havea notched Izod impact strength of greater than or equal to about 20kilojoules/square meter.

The specific volume resistivity is measured on a fractured dog bonesample having an injection-molded length of 30 centimeters prior to thefracturing. The sample is fractured under liquid nitrogen. Prior tofracturing, stress fracture lines are generated at a distance of 10centimeters apart on the surface of the sample. The sample is thenfractured under liquid nitrogen. After fracturing the sample, it issubjected to drying to remove any condensed moisture from the fracturedsurfaces. The fractured surfaces are then painted with a conductivesilver paint. The silver paint is then dried prior to making themeasurements. Resistance measurements or voltage measurements are madeby using a voltammeter. The electrodes of the voltammeter are applied tothe fracture surfaces to determine the resistance of the sample,following which the resistivity is calculated.

As noted above, the masterbatch can also contain non-electricallyconducting fillers and additives. Examples of suitable non-conductingelectrically conductive fillers are anti-oxidants, anti-ozonants, dyes,colorants, infrared light absorbers, ultraviolet light absorbers,reinforcing fillers, compatibilizers, plasticizers, fibers, or the like,or a combination comprising at least one of the foregoing non-conductivefillers.

An exemplary process for manufacturing the electrically conductivecomposition generally comprises melt blending. Melt blending of theelectrically conductive composition involves the use of shear force,extensional force, compressive force, ultrasonic energy, electromagneticenergy, thermal energy or combinations comprising at least one of theforegoing forces or forms of energy and is conducted in processingequipment wherein the aforementioned forces are exerted by a singlescrew, multiple screws, intermeshing co-rotating or counter rotatingscrews, non-intermeshing co-rotating or counter rotating screws,reciprocating screws, screws with pins, barrels with pins, rolls, rams,helical rotors, or combinations comprising at least one of theforegoing.

Melt blending involving the aforementioned forces may be conducted inmachines such as, single or multiple screw extruders, Buss kneader,Eirich mixers, Henschel, helicones, Ross mixer, Banbury, roll mills,molding machines such as injection molding machines, vacuum formingmachines, blow molding machines, or the like, or combinations comprisingat least one of the foregoing machines. It is generally desirable duringmelt or solution blending of the composition to impart a specific energyof about 0.01 to about 10 kilowatt-hour/kilogram (kwhr/kg) of thecomposition.

In one embodiment, in one method of manufacturing the electricallyconductive composition, it is desirable to melt a masterbatch comprisingup to about 50 wt % of the electrically conductive filler in a firstextruder. The molten masterbatch is diluted with the first polymer inthe first extruder and is fed into a second extruder containing themolten second polymer. Blending of the two melts occurs in the secondextruder. The electrically conductive composition comprising theelectrically conductive filler is extruded from the second extruder andthen pelletized.

In this arrangement, the first extruder serves as a side compounder tothe second extruder, which is the main extruder. In one embodiment, thefirst and the second extruders are twin screw extruders. In anotherembodiment, the first extruder can be a single screw extruder while thesecond extruder can be a twin screw extruder. The pelletized extrudatecan then be subjected to optional drying prior to injection molding.

In an exemplary embodiment, the masterbatch comprises nylon-6,6 andmultiwall carbon nanotubes in an amount of about 20 wt %, based upon thetotal weight of the masterbatch. The masterbatch is melted in the firstextruder and its melt viscosity is reduced by diluting the masterbatchwith additional nylon 6,6. The reduced viscosity molten masterbatch isthen fed from the first extruder into the second extruder. The secondextruder generally contains a compatibilized composition comprisingpolyphenylene ether and nylon-6,6. The compatibilized composition is thesecond polymer. It is desirable for the melt viscosity of the dilutedmasterbatch to be approximately equal to the melt viscosity of thesecond polymer at the point of contact of the two melts in the secondextruder. In one embodiment, the melt viscosity of the reduced viscositymolten masterbatch lies within about 10% of the melt viscosity of thesecond polymer at the point of contact of the two melts. In anotherembodiment, the melt viscosity of the reduced viscosity moltenmasterbatch lies within about 20% of the melt viscosity of the secondpolymer at the point of contact of the two melts.

The masterbatch can be diluted with the first polymer from about 10 wt %to about 1000 wt %, based upon the weight of the masterbatch. In oneembodiment, the masterbatch can be diluted with the first polymer fromabout 100 wt % to about 800 wt %, based upon the weight of themasterbatch. In another embodiment, the masterbatch can be diluted withthe first polymer from about 200 wt % to about 600 wt %, based upon theweight of the masterbatch. In yet another embodiment, the masterbatchcan be diluted with the first polymer from about 300 wt % to about 500wt %, based upon the weight of the masterbatch.

This method of manufacturing the electrically conductive composition isadvantageous in that the composition displays a uniform specific volumeresistivity in any two mutually perpendicular directions as comparedwith samples manufactured by other methods. In other words, there is areduction in the anisotropy in the electrical properties of theelectrically conductive composition when compared with compositionsmanufactured by other methods. In reducing the anisotropy, it ispreferable to have the ratio of volume resistivity (resistivity ratio)in the direction parallel to the flow direction to that in the directionperpendicular to the flow direction to be greater than or equal to about0.25. In one embodiment, it is desirable for the resistivity ratio to begreater than or equal to about 0.4. In another embodiment, it isdesirable for the resistivity ratio to be greater than or equal to about0.5. In yet another embodiment, it is desirable for the resistivityratio to be equal to 1. A sample having a resistivity ratio of 1 isbelieved to have no anisotropy. The flow direction as defined herein isthe direction of flow of the composition during the processing process.

The electrically conductive composition can be advantageously used inautomobiles, in particular, as exterior body panels. Other usefulapplications are in chip trays, computers, electronic goods,semi-conductor components, circuit boards, or the like which need to beprotected from electrostatic dissipation.

The following examples, which are meant to be exemplary, not limiting,illustrate compositions and methods of manufacturing of some of thevarious embodiments of the electrically conductive compositionsdescribed herein.

EXAMPLES

This example demonstrates the effect of reducing the melt viscosity ofthe masterbatch on the specific volume resistivity and the notched Izodimpact properties of the electrically conductive composition. In thisexample comparative samples were tested against the samples thatdemonstrate the improved method for production of the electricallyconductive compositions. The electrically conductive compositioncomprised a compatibilized blend of polyphenylene ether and nylon 6,6.The polyphenylene ether was obtained from General Electric AdvancedMaterials. The masterbatch comprises nylon 6,6 and multiwall carbonnanotubes. The multiwall carbon nanotubes were present in themasterbatch in and amount of 20 wt %, based on the weight of themasterbatch. The masterbatch was purchased from Hyperion Catalyts Inc.Citric acid was used to compatibilize the polyamide with thepolyphenylene ether. A mixture of copper iodide and potassium iodidealong with IRGANOX 1076® was used as the antioxidant. The impactmodifier used was KRATON G 1701X®, a styrene ethylene propylenecopolymer and KRATON G1651®, a styrene ethylene-butadiene styrenetriblock copolymer. Both impact modifiers are commercially availablefrom Kraton Polymers. The composition is shown in Table 1.

TABLE 1 Composition Weight percents (wt %) Polyphenylene ether 39.4Polyamide (Nylon 6,6) 46.4 Citric acid 0.65 IRGANOX 1076 ® 0.3 KRATON G1701X ® 3.5 KRATON G1651 ® 7 Carbon nanotube Masterbatch 3 Copper Iodide0.01 Potassium Iodide 0.05

FIG. 2 represents the extruder set up for the experiments. The mainextruder (second extruder) was a 28 mm Werner and Pfleiderer twin screwextruder. The extruder had 11 barrels set at temperatures of 50° C.,280° C., 300° C., 300° C., 300° C., 300° C., 290° C., 300° C., 300° C.,300° C., 300° C. and 300° C. respectively. The die was set at atemperature of 310° C. The screw speed was 300 revolutions per minute.The extruder had a side feeder located at barrel 6 and a side compounder(first extruder) located at barrel 9. As shown in the Table 2, thecomparative sample was prepared by feeding the polyphenylene ether alongwith the compatibilizers and other additives into the throat of thesecond extruder, while the nylon 6,6 and the masterbatch were fed intothe second extruder via the side feeder (SF). The side feeder feeds thenylon 6,6 and the masterbatch into the second extruder at roomtemperature.

TABLE 2 Throat of Second Extruder Side Feeder (SF) First ExtruderComparative Polyphenylene Nylon 6,6 + — Samples ether + additivesmasterbatch Samples Polyphenylene Nylon 6,6 Nylon 6,6 + manufacturedether + additives masterbatch according to disclosure

From the Table 2, it may be seen that those samples prepared accordingto this disclosure had the masterbatch and a portion of the nylon 6,6melt blended in the first extruder (side compounder (SC)) followingwhich they were fed into the second extruder. The remaining portion ofthe nylon 6,6 was fed into the second extruder at room temperature viathe side feeder.

The masterbatch was diluted with the nylon 6,6 in the first extruder ina weight ratio of masterbatch:nylon 6,6 of 1:2, 1:4, 1:5 and 1:6. Table3 shows the comparative sample as well as the samples made according tothis disclosure for electrically conductive compositions comprising 0.6wt % of the multiwall carbon nanotubes.

TABLE 3 Sample Comp. Sample Sample Sample Sample Sample 1 2 3 4 5 MWNT(wt %) 0.6 0.6 0.6 0.6 0.6 Masterbatch 0 1:2 1:4 1:5 1:6 dilutionMasterbatch SF* SC** SC SC SC Feeding position Izod Notched 23 22 22.822.2 22.2 Impact @ RT [kJ/m²] SVR (kOhm- 114286 92480 92309 50434 51017cm) *SF = side feeder; **SC = first extruder (side compounder)

Table 3 shows that the comparative sample 1 has a specific volumeresistivity (SVR) of 114,286 kiloohm-centimeter. However, samples thatare diluted with the nylon 6,6 in the first extruder (side compounder)and then introduced in the molten state into the second extruder (mainextruder) have a reduced specific volume resistivity when compared withsamples where the masterbatch is introduced into the side feeder at roomtemperature.

Tables 4, 5 and 6 below show similar beneficial effects of masterbatchdilution on the specific volume resistivity at MWNT loadings of 0.8 wt%, 1 wt % and 1.2 wt respectively.

TABLE 4 Sample Comp. Sample Sample Sample Sample Sample 6 7 8 9 10 MWNT(wt %) 0.8 0.8 0.8 0.8 0.8 Masterbatch 0 1:2 1:4 1:5 1:6 dilutionMasterbatch SF SC SC SC SC Feeding position Izod Notched 23.2 22.2 22.322 22.7 Impact @ RT [kJ/m2] SVR (kOhm- 464 36.5 29.0 18.7 17.2 cm)

TABLE 5 Sample Comp. Sample Sample Sample Sample Sample 11 12 13 14 15MWNT (wt %) 1 1 1 1 1 Masterbatch 0 1:2 1:4 1:5 1:6 dilution MasterbatchSF SC SC SC SC Feeding position Izod Notched 24.1 22.5 20.7 21.7 21.4Impact @ RT [kJ/m2] SVR (kOhm- 11 2.2 2.6 1.7 2.0 cm)

TABLE 6 Sample Comp. Sample Sample Sample Sample Sample 16 17 18 19 20MWNT (wt %) 1.2 1.2 1.2 1.2 1.2 Molten 0 1:2 1:4 1:5 1:6 Masterbatchdilution Masterbatch SF SC SC SC SC Feeding position Izod Notched 23.122 19.2 20.8 18.9 Impact @ RT [kJ/m2] SVR (kOhm- 2.6 0.4 0.9 0.8 0.8 cm)

From the Tables 3, 4, 5 and 6 it may be seen that as the level ofdilution in the first extruder increases, the volume resistivity of thesample decreases, indicating that the reduced viscosity brought about bythe dilution of the masterbatch improves the dispersion. Without beinglimited by theory, it is believed that the reduction in viscosity playsan important role in the optimization of the dispersion, which permits areduction in the resistivity of the compositions. Alternatively, byreducing the resistivity of the compositions, a lower amount ofelectrically conductively filler can be used thereby reducing materialcosts as well as reducing the amount of processing required and theenergy expenditures accompanying this processing.

Articles made by the aforementioned method can be advantageously used inautomobiles for parts such as automotive exterior body panels, fenders,dashboards, or the like.

While the invention has been described with reference to exemplaryembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims.

1. A method of manufacturing an electrically conductive compositioncomprising: reducing a melt viscosity of an electrically conductivemolten masterbatch comprising a polymer and an electrically conductivefiller, to form a reduced viscosity molten masterbatch; wherein the meltviscosity of the electrically conductive molten masterbatch is reducedby mixing it with a diluent, a plasticizer, a polymer having a meltviscosity that is lower than the melt viscosity of the electricallyconductive molten masterbatch, or a combination thereof, and mixing thereduced viscosity molten masterbatch with a molten second polymer toform the electrically conductive composition; wherein a melt viscosityof the reduced viscosity molten masterbatch is equal to a melt viscosityof the molten second polymer at an initial point of contact.
 2. A methodof manufacturing an electrically conductive composition comprising:mixing an electrically conductive molten masterbatch comprising apolymer and an electrically conductive filler with a first polymer in afirst extruder, wherein the first polymer has a melt viscosity that islower than a melt viscosity of the electrically conductive moltenmasterbatch; reducing the melt viscosity of the electrically conductivemolten masterbatch to form a reduced viscosity molten masterbatch; andmixing the reduced viscosity molten masterbatch with a second polymer ina second extruder to form the electrically conductive composition;wherein a melt viscosity of the reduced viscosity molten masterbatch isequal to a melt viscosity of the second polymer at an initial point ofcontact in the second extruder.
 3. The method of claim 2, wherein theelectrically conductive filler is carbon black, carbon nanotubes, carbonfibers, metallic fillers, non-conductive fillers coated with metalliccoatings, electrically conductive non-metallic fillers, or a combinationcomprising at least one of the foregoing electrically conductivefillers.
 4. The method of claim 3, wherein the carbon nanotubes aresingle wall carbon nanotubes, multiwall carbon nanotubes, vapor growncarbon fibers, or a combination comprising at least one of the foregoingcarbon nanotubes.
 5. The method of claim 2, wherein the electricallyconductive molten masterbatch comprises up to about 50 wt % of theelectrically conductive fillers, based on the weight of the electricallyconductive molten masterbatch.
 6. The method of claim 2, wherein thefirst extruder is a side compounder to the second extruder.
 7. Themethod of claim 2, wherein the first polymer is the same as the secondpolymer.
 8. The method of claim 2, wherein the first polymer isdifferent from the second polymer.
 9. The method of claim 2, wherein thefirst polymer and the second polymer are compatibilized in theelectrically conductive composition.
 10. The method of claim 2, whereinthe first polymer and/or the second polymer is a thermoplastic, athermoset, or a combination of a thermoplastic with a thermoset.
 11. Themethod of claim 2, wherein the first polymer and/or the second polymeris a polyacetal, a polyacrylic, a polyarylene ether, a polycarbonate, apolystyrene, a polyester, a polyamide, a polyamideimide, a polyarylate,a polyurethane, a polyarylsulfone, a polyethersulfone, a polyarylenesulfide, a polyvinyl chloride, a polyetherimide, a polyimide, apolytetrafluoroethylene, a polyetherketone, a polyether ether ketone ora combination comprising at least one of the foregoing polymeric resins.12. The method of claim 2, wherein the first polymer is a polyamide andwherein the second polymer is a polyarylene ether.
 13. The method ofclaim 2, wherein the electrically conductive composition comprises acompatibilizer and an impact modifier.
 14. The method of claim 2,wherein the electrically conductive composition has a specific volumeresistivity of less than or equal to about 10e⁸ ohm-cm, a notched Izodimpact strength of greater than 10 kilojoules/square meter and a Class Asurface finish.
 15. The method of claim 2, wherein the electricallyconductive composition has a specific volume resistivity of less than orequal to about 10e⁸ ohm-cm and a notched Izod impact strength of greaterthan 15 kilojoules/square meter.
 16. The method of claim 2, wherein theelectrically conductive composition has a specific volume resistivity ofless than or equal to about 10e⁸ ohm-cm, a notched Izod impact strengthof greater than 10 kilojoules/square meter and a Class A surface finish.17. An article manufactured by the method of claim 3, wherein theresistivity ratio of the electrically conductive composition is greaterthan or equal to 0.5.
 18. The article of claim 17, wherein the articleis an automobile part.
 19. The article of claim 18, wherein theautomobile part is an exterior body panel, a fender or a dashboard. 20.A method of manufacturing an electrically conductive compositioncomprising: mixing an electrically conductive molten masterbatchcomprising a polyamide and an electrically conductive filler with apolyamide in a first extruder, wherein the polyamide has a meltviscosity that is lower than a melt viscosity of the molten masterbatch;reducing the melt viscosity of the molten masterbatch to form a reducedviscosity molten masterbatch; and mixing the reduced viscosity moltenmasterbatch with a molten polyarylene ether in a second extruder to formthe electrically conductive composition wherein a melt viscosity of thereduced viscosity molten masterbatch is equal to a melt viscosity of thepolyarylene ether at an initial point of contact in the second extruder.21. The method of claim 20, wherein the molten masterbatch comprises apolyamide and carbon nanotubes.
 22. The method of claim 20, wherein thepolyarylene ether is compatibilized with a polyamide prior to the mixingwith the reduced viscosity molten masterbatch.
 23. The method of claim20, further comprising molding the electrically conductive composition.24. An article manufactured by the method of claim 20, wherein theresistivity ratio of the electrically conductive composition is greaterthan or equal to 0.5.
 25. The article of claim 24, wherein the articleis an automobile part.
 26. The article of claim 25, wherein theautomobile part is an exterior body panel, a fender or a dashboard. 27.A method of manufacturing a composition comprising: melting amasterbatch comprising a polymer and an electrically conductive fillerto form an electrically conductive molten masterbatch in a firstextruder; reducing the viscosity of the electrically conductive moltenmasterbatch in the first extruder; and mixing the reduced viscositymolten masterbatch with a molten second polymer in a second extruder toform the composition wherein a melt viscosity of the reduced viscositymolten masterbatch is equal to a melt viscosity of the second polymer atan initial point of contact in the second extruder.
 28. The method ofclaim 27, wherein the masterbatch further comprises fillers and/oradditives that are non-electrically conductive.
 29. The method of claim28, wherein the non-electrically conductive fillers are anti-oxidants,anti-ozonants, dyes, colorants, infrared light absorbers, ultravioletlight absorbers, reinforcing fillers, compatibilizers, plasticizers,fibers, or a combination comprising at least one of the foregoingnon-conductive fillers.
 30. An article manufactured by the method ofclaim 29, wherein the resistivity ratio of the electrically conductivecomposition is greater than or equal to 0.5.